sensor: Fix samples that assume incorrect sensor_value type.

Various sensor samples are hardwired to expect returned sensor values
are represented as doubles.  In each case this assumption is incorrect.

Introduce a generic sensor_value to double helper function and adjust
the samples to use it.

Change-Id: I89c788686576562b84e07a36064640231340c33b
Signed-off-by: Marcus Shawcroft <marcus.shawcroft@arm.com>

include/sensor.h

@@ -458,6 +458,24 @@ static inline void sensor_degrees_to_rad(int32_t d, struct sensor_value *rad)
 	rad->val2 = ((int64_t)d * SENSOR_PI / 180LL) % 1000000LL;
 }
 
+/**
+ * @brief Helper function for converting struct sensor_value to double.
+ *
+ * @param val A pointer to a sensor_value struct.
+ * @return The converted value.
+ */
+static inline double sensor_value_to_double(struct sensor_value *val)
+{
+	switch (val->type) {
+	case SENSOR_VALUE_TYPE_INT_PLUS_MICRO:
+		return (double)val->val1 + (double)val->val2 / 1000000;
+	case SENSOR_VALUE_TYPE_DOUBLE:
+		return val->dval;
+	}
+
+	return 0.0;
+}
+
 /**
  * @brief configuration parameters for sensor triggers.
  */

samples/grove/light/src/main.c

@@ -36,9 +36,8 @@ void main(void)
 		sensor_sample_fetch(dev);
 		sensor_channel_get(dev, SENSOR_CHAN_LIGHT, &lux);
 
-		printf("lux: %f\n", lux.dval);
+		printf("lux: %f\n", sensor_value_to_double(&lux));
 
 		k_sleep(SLEEP_TIME);
 	}
 }
-

samples/grove/temperature/src/main.c

@@ -67,13 +67,14 @@ void main(void)
 
 		/* display temperature on LCD */
 		glcd_cursor_pos_set(glcd, 0, 0);
-		sprintf(row, "T:%.2f%cC", temp.dval, 223 /* degree symbol */);
+		sprintf(row, "T:%.2f%cC",
+			sensor_value_to_double(&temp),
+			223 /* degree symbol */);
 		glcd_print(glcd, row, strlen(row));
 
 #endif
-		printf("Temperature: %.2f C\n", temp.dval);
+		printf("Temperature: %.2f C\n", sensor_value_to_double(&temp));
 
 		k_sleep(SLEEP_TIME);
 	}
 }
-

samples/sensor/magn_polling/src/main.c

@@ -35,7 +35,10 @@ static void do_main(struct device *dev)
 		ret = sensor_channel_get(dev, SENSOR_CHAN_MAGN_X, &value_x);
 		ret = sensor_channel_get(dev, SENSOR_CHAN_MAGN_Y, &value_y);
 		ret = sensor_channel_get(dev, SENSOR_CHAN_MAGN_Z, &value_z);
-		printf("( x y z ) = ( %f  %f  %f )\n", value_x.dval, value_y.dval, value_z.dval);
+		printf("( x y z ) = ( %f  %f  %f )\n",
+		       sensor_value_to_double(&value_x),
+		       sensor_value_to_double(&value_y),
+		       sensor_value_to_double(&value_z));
 
 		k_sleep(500);
 	}

samples/sensor/max44009/src/main.c

@@ -50,7 +50,7 @@ void main(void)
 			return;
 		}
 
-		lum = val.dval;
+		lum = val.val1;
 		printk("sensor: lum reading: %d\n", lum);
 
 		k_sleep(4000);

samples/sensor/th02/src/main.c

@@ -99,12 +99,14 @@ void main(void)
 
 		/* display temperature on LCD */
 		glcd_cursor_pos_set(glcd, 0, 0);
-		sprintf(row, "T:%.1f%cC", val[0].dval, 223 /* degree symbol */);
+		sprintf(row, "T:%.1f%cC", sensor_value_to_double(val),
+			223 /* degree symbol */);
 		glcd_print(glcd, row, strlen(row));
 
 		/* display himidity on LCD */
 		glcd_cursor_pos_set(glcd, 17 - strlen(row), 0);
-		sprintf(row, "RH:%.0f%c", val[1].dval, 37 /* percent symbol */);
+		sprintf(row, "RH:%.0f%c", sensor_value_to_double(val + 1),
+			37 /* percent symbol */);
 		glcd_print(glcd, row, strlen(row));
 
 #endif